Synergistically active herbicidal mixtures

ABSTRACT

A composition which comprises 
     a) at least one sulfonylurea of the formula I:                    
     wherein the radicals R 1  to R 5  and the index n are as defined in the specification, or an enviromentally compatible salt of the sulfonylurea, and 
     b) at least one herbicidal compound selected from groups b 1  to b 41  as defined in the specification, or an environmentally compatible salt of the herbicidal compound, 
     and which exhibits a synergistic herbicidal effect.

This is a Divisional Application of application Ser. No. 09/043,314, filed on Feb. 17, 1998, under 35 U.S.C. §371 now U.S. Pat. No. 6,054,410, which is a 371 of PCT/EP96/03996 filed Sep. 12, 1996.

The present invention relates to a synergistically active herbicidal mixture composed of a sulfonylurea derivative (a) of the formula I and one or more herbicidal compounds b1 to 41.

Herbicidally active sulfonylureas of the formula I have been disclosed in the prior art, for example in EP-388 873, EP-559 814, EP-291 851 and DE-40 07 683 and the Conference Proceedings “Fluorine in Agriculture”, Jan. 9-11 1995, Manchester, chapter “New Fluoro Intermediates for Herbicidal Sulfonylureas”.

Herbicidal compounds b1 to b41 are described, for example, in “Herbizide”, Hock, Fedtke, Schmidt, 1st Edition, Thieme 1995 (see “quinclorac” p. 238, “molinate” p. 32, “butachlor” p. 32, “pretilachlor” p. 32, “dithiopyr” p. 32, “mefenacet” p. 32, “fenoxapropethyl” p. 216, “dimepiperate” p. 32, “pyrazolate” p. 146, “pyrazoxyfen” p. 146, “bensulfuron-methyl” p. 31, “pyrazosulfuron-ethyl” p. 31, “cinosulfuron” p. 31, “benfuresate” p. 233, “bromobutide” p. 243, “dymrone” p. 243, “dimethyametryn ” p. 118, “esprocarb” p. 229, “pyributicarb” p. 32, “cinemthylin” p. 32, “propanil” p. 32, “2,4-D” p. 30, “bentazone” p. 30, “DPX-A-8947” p. 175, “mecoprop-P” p. 237, “chlorpropham” p. 205, “thiocarbazil” p. 229, “ethoxyfen” p. 30, “haloxyfop-P-methyl” p. 38, “haloxyfop-ethoxyethyl” p. 38, “flumiclorac-pentyl” p. 35, “flupropacil” p. 143, “nipyraclofen” p. 145, “metosulam” p. 33, “ethametsulfuron-methyl” p. 36, “thifensulfuron-methyl” p. 35 or in “Agricultural Chemicals”, Book II Herbicides, 1993 see “thiobencarb” p. 85, “benzofenap” p. 221, “napropanilid” p. 49, “piperophos” p. 102, “anilofos” p. 241, “TH-913” p. 150, “HW-52” p. 54, “ICIA-0051” p. 268, “poast” p. 253, “focus” p. 222, “dimethenamid” p. 48, “sulfosaten ” p. 236, “2,4-DB” p. 10, “dichlorprop-P” p. 6, “flupoxam” p. 44, “prosulfocarb” p. 84, “quinmerac” p. 233, “metazachlor” p. 64, “flurtamone” p. 265, “bromofenoxim” p. 228, “fomesafen” p. 248, “imazethabenz-methyl” p. 153, “clodinafop” p. 214, “fenoxaprop-P-ethyl” p. 208, “fluazifop-P-butyl” p. 207, “quizalofop-P-ethyl” p. 210, “quizalofop-terfuryl” p. 211, “flumioxazin” p. 43, “flumipropyn” p. 267, “sulfentrazone” p. 261, “thiazopyr” p. 226, “pyrithiobac-sodium” p. 266, “flumetsulam” p. 227, “amidosulfuron” p. 151, “halosulfuron-methyl” p. 148, “rimsulfuron” p. 138, “tribenuron-methyl” p. 139, “triflusulfuron-methyl” p. 137, “primisulfuron” p. 147 or in “Short Review of Herbicides & PGRs 1991, Hodogaya Chemicals see “furyloxyfen” p. 142, “triazofenamid” p. 268, “KH-218” p. 52, “NSK-850” p. 52, “JC-940” p. 90, “AC-92553” p. 58, “buthidazole” p. 88, “cyprazole” p. 38, “allidochlor” p. 48, “benzoylprop-ethyl” p. 38, “chlorthiamid” p. 150 “diphenamid” p. 34, “flamprop-methyl” p. 40, “fosamin” p. 232, “isoxaben” p. 42, “monalide” p. 32, “naptalam” p. 36, “pronamid” p. 34, “bialaphos” p. 234, “glufosinate-ammonium” p. 234, “glyphosates” p. 232, “amitrol” p. 254, “clomeprop” p. 20, “dichlorprop” p. 6, “fenoprop” p. 8, “fluroxypyr” p. 156, “MCPA” p. 4, “MCPB” p. 8, “mecoprop” p. 6, “napropamide” p. 16, “triclopyr” p. 154, “chloramben” p. 28, “dicamba” p. 26, “clomazone” p. 268, “diflufenican” p. 42, “fluorochloridone” p. 266, “fluridone” p. 156, “asulam” p. 112, “barban” p. 100, “butylate” p. 106, “carbetamide” p. 36, “chlorobufam” p. 100, “cycloate” p. 108, “desmedipham” p. 104, “di-allate” p. 106, “EPTC” p. 108, “orbencarb” p. 112, “pebulate” p. 106, “phenisopham” p. 118, “pendimedipham” p. 104, “propham” p. 100, “sulf-allate” p. 110, “terbucarb” p. 102, “tri-allate” p. 108, “vernolate” p. 108, “acetochlor” p. 48, “alachlor” p. 46, “diethathyl-ethyl” p. 48, “dimethachlor” p. 50, “metolachlor” p. 46, “propachlor” p. 44, “pyrnachlor” p. 44, “terbuchlor” p. 48, “xylachlor” p. 52, “alloxydim” p. 260, “clethodim” p. 270, “cloproxydim” p. 268, “tralkoxydim” p. 270, “dalapon” p. 212, “ethofumesate” p. 124, “benefin” p. 54, “butralin” p. 58, “dinitramin” p. 56, “ethalfluralin” p. 60, “fluchloralin” p. 54, “isopropalin” p. 58, “nitralin” p. 58, “oryzalin” p. 60, “prodiamine” p. 62, “profluralin” p. 54, “trifluralin” p. 54, “dinoseb” p. 128, “dinoseb-acetate” p. 128, “dinoterb” p. 128, “DNOC” p. 126, “acilfluorfen-sodium” p. 142, “aclonifen” p. 146, “bifenox” p. 140, “chlornitrofen” p. 138, “difenoxuron” p. 76, “fluorodifen” p. 138, “fluoroglycofen-ethyl” p. 146, “lactofen” p. 144, “nitrofen” p. 136, “nitrofluorfen” p. 140, “oxyfluorfen” p. 140, “cyperquat” p. 158, “difenzoquat” p. 160, “diquat” p. 158, “paraquat” p. 158, “benzthiazuron” p. 82, “buturon” p. 66, “chlorbromuron” p. 72, “chloroxuron” p. 76, “chlortoluron” p. 74, “cycluron” p. 84, “dimeturon” p. 88, “diuron” p. 70, “ethidimuron” p. 86, “fenuron” p. 64, “fluometuron” p. 68, “isoproturon” p. 80, “isouron” p. 88, “karbutilate” p. 76, “linuron” p. 72, “methabenzthiazuron” p. 82, “metoxuron” p. 72, “monolinuron” p. 66, “monuron” p. 64, “neburon” p. 72, “siduron ” p. 68, “tebuthiuron” p. 86, “trimeturon” p. 64, “isocarbamid” p. 168, “imazamethapyr” p. 172, “imazapyr” p. 170, “imazaquin” p. 170, “imazethapyr” p. 172, “methazole” p. 162, “oxadiazon” p. 162, “tridiphane” p. 266, “bromoxynil” p. 148, “ioxynil” p. 148, “diclofop-methyl” p. 16, “fenthiaprop-ethyl” p. 20, “fluazifop-butyl” p. 18, “haloxyfop-methyl” p. 18, “isoxapyrifop” p. 22, “propaquizafop” p. 24, “quizalofop-ethyl” p. 20, “chlorfenac” p. 258, “chlorophenprop-methyl” p. 258, “chloridazon” p. 174, “maleic hydrazide” p. 162, “norflurazon” p. 174, “pyridate” p. 176, “clopyralid” p. 154, “picloram,” p. 154, “chlorimuron-ethyl” p. 92, “chlorsulfuron” p. 92, “flazasulfuron” p. 96, “metsulfuron-methyl” p.92, “nicosulfuron” p. 96, “sulfometuron-methyl” p. 92, “triasulfuron” p. 94, “ametryn” p. 198, “atrazine” p. 188, “aziprotryne” p. 206, “cyanazine” p. 192, “cyprazine” p. 192, “desmetryne” p. 200, “dipropetryn” p. 202, “eglinazine-ethyl” p. 208, “hexazinon” p. 208, “procyazine” p. 192, “prometone” p. 196, “prometryn” p. 196, “propazine” p. 188 “secbumeton” p. 196, “simazine” p. 188, “simetryn” p. 196, “terbumeton” p. 204, “terbutryn” p. 198, “terbuthylazine” p. 190, “trietazine” p. 188, “ethiozin” p. 210, “metamitron” p. 206, “metribuzin” p. 202, “bromacil” p. 180, “lenacil” p. 180, “terbacil” p. 180, “benazolin” p. 262, “bensulide” p. 228, “benzofluor” p. 266, “butamifos” p. 228, “DCPA” p. 28, “dichlobenil” p. 148, “endothal” p. 264, “mefluidide” p. 306, “perfluidone” p. 260, “terbuchlor” p. 48 or in “Global Herbicide Directory” First Edition, 1994 see “oxadiargyl” p. 96, or in “European Directory of Agrochemical Products Volume 2—Herbicides” Fourth Edition, see “buminafos” p. 255. The compound “DEH-112” is disclosed in European Patent Application EP 0 302 203. The compound “caloxydim” is described in DE 3 336 140, the compound “cinidon-ethyl” in DE 3 603 789 and the compound “fluorbentranil” in EP 84 893. “Other compounds are known from “Brighton Crop Protection Conference—Weeds —1993 (see “thidiazimin” p. 29, “AC-322140” p. 41, “KIH-6127” p. 47, “prosulfuron” p. 53, “KIH-2023” p. 61, “metobenzuron” p. 67). The compound “CH-900” is described in EP 0 332 133.

In principle, it is desirable in crop protection products to increase the specific activity of an active ingredient and the reliability of its action. It was therefore the object of the present invention to increase the activity of known, herbicidally active sulfonylureas of the formula I.

We have found that this object is achieved by a herbicidal mixture which comprises.

a) at least one derivative of the sulfonylurea of the formula I:

 where the substituents have the following meanings:

R¹ is C₁-C₆-alkyl which has attached to it one to five of the following groups: methoxy, ethoxy, SO₂CH₃, cyano, chlorine, fluorine, SCH₃, S(O)CH₃; halogen; a group ER⁶ where E is O, S or NR⁷; COOR⁸; NO₂; S(O)_(o)R⁹, SO₂NR¹⁰R¹¹, CONR¹⁰R¹¹;

R² is hydrogen, C₁-C₄-alkyl, C₂-C₄-alkenyl, C₂-C₄-alkynyl, halogen, C₁-C₄-alkoxy, C₁-C₄-haloalkoxy; C₁-C₄-haloalkyl, a C₁-C₂--alkylsulfonyl group, nitro, cyano or C₁-C₄-alkylthio;

R³ is F, CF₃, CF₂Cl, CF₂H, OCF₃, OCF₂Cl, or, if R¹ is CO₂CH₃ and R² is simultaneosly fluorine, R³ is Cl, or, if R¹ is CH₂CF₃ or CF₂CF₃, R³ is methyl, or, if R⁴ is OCF₃ or OCF₂Cl, R³ is OCF₂H or OCF2Br;

R⁴ is C₁-C₂-alkoxy, C₁-C₂-alkyl, C₁-C₂-alkylthio, C₁-C2-alkylamino, di-C₁-C₂-alkylamino, halogen, C₁-C₂-haloalkyl, C₁-C₂-haloalkoxy,

R⁵ is hydrogen, C₁-C₂-alkoxy, C₁-C₄-alkyl;

R⁶ is C₁-C₄-alkyl, C₂-C₄-alkenyl, C₂-C₄-alkynyl or C₃-C₆-cycloalkyl, all of which can have attached to them. 1 to 5 halogen atoms, with the exception of allyl, difluoromethoxy, chlorodifluoromethoxy and 2-chloroethoxy, if E is O or S. In the event that E is O or NR⁷, R⁶ is furthermore also methylsulfonyl, ethylsulfonyl, trifluoromethylsulfonyl, allylsulfonyl, propargylsulfonyl or dimethylsulfamoyl;

R⁷ is hydrogen, methyl or ethyl

R⁸ is a C₁-C₆-alkyl group which can have attached to it up to three of the following radicals: halogen, C₁-C₄-alkoxy, C₁-C₄-alkylthio, C₁-C₄-haloalkoxy, C₁-C₄-alkoxy-C₁-C₂-alkoxy, C₃-C₇-cycloalkyl and/or phenyl; a C₅-C₇-cycloalkyl group which can have attached to it up to three C₁-C₄-alkyl groups; C₃-C₆-alkenyl or C₃-C₆-alkynyl;

R⁹ is a C₁-C₆-alkyl group which can have attached to it one to three of the following radicals: halogen, C₁-C₄-alkoxy, C₁-C₄-alkylthio, C₁-C₄-haloalkoxy, C₁-C₄-alkoxy-C₁-C₂-alkoxy, C₃-C₇-cycloalkyl and/or phenyl; a C₅-C₇-cycloalkyl group which can have attached to it one to three C₁-C₄-alkyl groups; a C₃-C₆-alkenyl group or a C₃-C₆-alkynyl group;

R¹⁰ is hydrogen, a C₁-C₂-alkoxy group, a C₁-C₆-alkyl group, or together with R¹¹ is a C₄-C₆-alkylene chain in which one methylene group can be replaced by an oxygen atom or a C₁-C₄-alkylimino group;

R¹¹ is a C₁-C₄-alkyl group which can have attached to it one to four halogen or C₁-C₄-alkoxy radicals; C₃-C₆-cycloalkyl

n is 0-3

o is 1-2

Z N or CH, and

b) a synergistically active amount of at least one herbicidal compound selected from the groups b1 to b41

b1 1,3,4-thiadiazoles: buthidazole, cyprazole

b2 amides: allidochlor (CDAA), benzoylprop-ethyl, bromobutide, chlorthiamid, dimepiperate, dimethenamid, diphenamid, etobenzanid (benzchlomet), flamprop-methyl, fosamin, isoxaben, monalide, naptalame, pronamid (propyzamid), propanil

b3 aminophosphoric acids: bilanafos, (bialaphos), buminafos, glufosinate-ammonium, glyphosate, sulfosate

b4 aminotriazoles: amitrol

b5 anilides: anilofos, mefenacet

b6 aryloxyalkanoic acids: 2,4-D, 2,4-DB, clomeprop, dichlorprop, dichlorprop-P, dichlorprop-P (2,4-DP-P), fenoprop (2,4,5-TP), fluoroxy-pyr, MCPA, MCPB, mecoprop, mecoprop-P, napropamide, napropanilide, triclopyr

b7 benzoic acids: chloramben, dicamba

b8 benzothiadiazinones: bentazone

b9 bleaches: clomazone (dimethazone), diflufenican, fluorochloridone, flupoxam, fluridone, pyrazolate, sulcotrione (chlormesulone)

b10 carbamates: asulam, barban, butylate, carbetamid, chlorbufam, chlorpropham, cycloate, desmedipham, di-allate, EPTC, esprocarb, molinate, orbencarb, pebulate, phenisopham, phenmedipham, propham, prosulfocarb, pyributicarb, sulf-allate (CDEC), terbucarb, thiobencarb (benthiocarb), tiocarbazil, tri-allate, vernolate

b11 quinolinecarboxylic acids: quinclorac, quinmerac

b12 chloracetanilides: acetochlor, alachlor, butachlor, butenachlor, diethatylethyl, dimethachlor, metazachlor, metolachlor, pretilachlor, propachlor, prynachlor, terbuchlor, thenylchlor, xylachlor

b13 cyclohexenones: alloxydim, caloxydim, clethodim, cloproxydim, cycloxydim, sethoxydim, tralkoxydim, 2-{1-[2-(4-chlorophenoxy)propyloxyimino]butyl}-3-hydroxy-5-(2H-tetrahydrothiopyran-3-yl)-2-cyclohexen-1-one

b14 dichloropropionic acids: dalapon

b15 dihydrobenzofurans: ethofumesate

b16 dihydrofuran-3-ones: flurtamone

b17 dinitroanilines: benefin, butralin, dinitramin, ethalfluralin, fluchloralin, isopropalin, nitralin, oryzalin, pendimethalin, prodiamine, profluralin, trifluralin

b18 dinitrophenols: bromofenoxim, dinoseb, dinoseb-acetate, dinoterb, DNOC

b19 diphenyl ethers: acifluorfen-sodium, aclonifen, bifenox, chlornitrofen (CNP), difenoxuron, ethoxyfen, fluorodifen, fluoroglycofen-ethyl, fomesafen, furyloxyfen, lactofen, nitrofen, nitrofluorfen, oxyfluorfen

b20 dipyridylenes: cyperquat, difenzoquat methylsulfate, diquat, paraquat dichloride

b21 ureas: benzthiazuron, buturon, chlorbromuron, chloroxuron, chlortoluron, cumyluron, dibenzyluron, cycluron, dimefuron, diuron, dymrone, ethidimuron, fenuron, fluometuron, isoproturon, isouron, karbutilate, linuron, methabenzthiazuron, metobenzuron, metoxuron, monolinuron, monuron, neburon, siduron, tebuthiuron, trimeturon

b22 imidazoles: isocarbamid

b23 imidazolinones: imazamethapyr, imazapyr, imazaquin, imazethabenz-methyl (imazame), imazethapyr

b24 oxadiazoles: methazole, oxadiargyl, oxadiazon

b25 oxiranes: tridiphane

b26 phenols: bromoxynil, ioxynil

b27 phenoxyphenoxypropionic esters: clodinafop, cyhalofop-butyl, diclofop-methyl, fenoxapropethyl, fenoxaprop-P-ethyl, fenthiapropethyl, fluazifopbutyl, fluazifop-P-butyl, haloxyfop-ethoxyethyl, haloxy-fop-methyl, haloxyfop-P-methyl, isoxapyrifop, propaquizafop, quizalofop-ethyl, quizalofop-P-ethyl, quizalofop-tefuryl

b28 phenylacetic acids: chlorfenac (fenac)

b29 phenylpropionic acid: chlorophenprop-methyl

b30 protoporphyrinogen IX oxydase inhibitors: benzofenap, cinidon-ethyl, flumiclorac-pentyl, flumioxazin, flumipropyn, flupropacil, fluthiacet-methyl, pyrazoxyfen, sulfentrazone, thidiazimin

b31 pyrazoles: nipyraclofen

b32 pyridazines: chloridazon, maleic hydrazide, norflurazon, pyridate

b33 pyridinecarboxylic acids: clopyralid, dithiopyr, picloram, thiazopyr

b34 pyrimidyl ethers: pyrithiobac acid, pyrithiobac sodium, KIH-2023, KIH-6127

b35 sulfonamides: flumetsulam, metosulam

b36 sulfonylureas: amidosulfuron, azimsulfuron, bensulfuron-methyl, chlorimuron-ethyl, chlorsulfuron, cinosulfuron, cyclosulfamuron, ethametsulfuron-methyl, ethoxysulfuron, flazasulfuron, halosulfuron-methyl, imazosulfuron, metsulfuron-methyl, nicosulfuron, primisulfuron, prosulfuron, pyrazosulfuron-ethyl, rimsulfuron, sulfometuron-methyl, thifensulfuron-methyl, triasulfuron, tribenuron-methyl, triflusulfuron-methyl

b37 triazines: ametryn, atrazine, aziprotryn, cyanazine, cyprazine, desmetryn, dimethamethryn, dipropetryn, eglinazine-ethyl, hexazinon, procyazine, prometon, prometryn, propazine, secbumeton, simazine, simetryn, terbumeton, terbutryn, terbuthylazine, trietazine

b38 triazinones: ethiozin, metamitron, metribuzin

b39 triazolecarboxamides: triazofenamid

b40 uracils: bromacil, lenacil, terbacil

b41 others: benazolin, benfuresate, bensulide, benzofluor, butamifos, cafenstrole, chlorthal-dimethyl (DCPA), cinmethylin, dichlobenil, endothall, fluorbentranil, mefluidide, perfluidone, piperophos

or their environmentally compatible salts.

The herbicidal mixture according to the invention has superadditive synergistic action and is selective for those crop plants which also tolerate the individual compounds themselves.

Especially preferred sulfonylureas of the formula I with a view to their synergistic herbicidal action are those where

R¹ is CO₂CH₃, CO₂C₂H₅, CO₂iC₃H₇, CF₃, CF₂H; OSO₂CH₃, OSO₂N(CH₃)₂, Cl, NO₂, SO₂N(CH₃)₂, SO₂CH₃ and N(CH₃)SO₂CH₃

R² is hydrogen, Cl, F or C₁-C₂-alkyl

R³ is CF₂H, OCF₃, OCF₂Cl, CF₂Cl, CF₃ or F

R⁴ is OCH₃, OC₂H₅, OCF₃, OCF₂Cl; CF₃, Cl, F, NH(CH₃), N(CH₃)₂ or C₁-C₂-alkyl

R⁵ hydrogen,

Z N or CH and

n 0 or 1.

preferred compounds of the formula I are compiled in the table which follows.

TABLE

No. R¹ R² R⁵ R³ R⁴ Z  1 CO₂CH₃ H H OCF₂Cl OCH₃ CH  2 CO₂C₂H₅ H H OCF₂Cl OCH₃ CH  3 CO₂iC₃H₇ H H OCF₂Cl OCH₃ CH  4 NO₂ H H OCF₂Cl OCH₃ CH  5 SO₂CH₃ H H OCF₂Cl OCH₃ CH  6 SO₂N(CH₃)₂ H H OCF₂Cl OCH₃ CH  7 Cl H H OCF₂Cl OCH₃ CH  8 N(CH₃)SO₂CH₃ H H OCF₂Cl OCH₃ CH  9 OSO₂CH₃ H H OCF₂Cl OCH₃ CH 10 OSO₂N(CH₃)₂ H H OCF₂Cl OCH₃ CH 11 CF₃ H H OCF₂Cl OCH₃ CH 12 CF₂H H H OCF₂Cl OCH₃ CH 13 CO₂CH₃ H H OCF₃ OCH₃ CH 14 CO₂C₂H₅ H H OCF₃ OCH₃ CH 15 CO₂iC₃H₇ H H OCF₃ OCH₃ CH 16 NO₂ H H OCF₃ OCH₃ CH 17 SO₂CH₃ H H OCF₃ OCH₃ CH 18 SO₂N(CH₃)₂ H H OCF₃ OCH₃ CH 19 Cl H H OCF₃ OCH₃ CH 20 N(CH₃)SO₂CH₃ H H OCF₃ OCH₃ CH 21 OSO₂CH₃ H H OCF₃ OCH₃ CH 22 OSO₂N(CH₃)₂ H H OCF₃ OCH₃ CH 23 CF₃ H H OCF₃ OCH₃ CH 24 CF₂H H H OCF₃ OCH₃ CH 25 CO₂CH₃ H H F OCH₃ CH 26 CO₂C₂H₅ H H F OCH₃ CH 27 CO₂iC₃H₇ H H F OCH₃ CH 28 NO₂ H H F OCH₃ CH 29 SO₂CH₃ H H F OCH₃ CH 30 SO₂N(CH₃)₂ H H F OCH₃ CH 31 Cl H H F OCH₃ CH 32 N(CH₃)SO₂CH₃ H H F OCH₃ CH 33 OSO₂CH₃ H H F OCH₃ CH 34 OSO₂N(CH₃)₂ H H F OCH₃ CH 35 CF₃ H H F OCH₃ CH 36 CF₂H H H F OCH₃ CH 37 CO₂CH₃ H H CF₃ OCH₃ N 38 CO₂C₂H₅ H H CF₃ OCH₃ N 39 CO₂iC₃H₇ H H CF₃ OCH₃ N 40 NO₂ H H CF₃ OCH₃ N 41 SO₂CH₃ H H CF₃ OCH₃ N 42 SO₂N(CH₃)₂ H H CF₃ OCH₃ N 43 Cl H H CF₃ OCH₃ N 44 N(CH₃)SO₂CH₃ H H CF₃ OCH₃ N 45 OSO₂CH₃ H H CF₃ OCH₃ N 46 OSO₂N(CH₃)₂ H H CF₃ OCH₃ N 47 CF₃ H H CF₃ OCH₃ N 48 CF₂H H H CF₃ OCH₃ N 49 CO₂CH₃ H H CF₃ OCH₃ CH 50 CO₂C₂H₅ H H CF₃ OCH₃ CH 51 CO₂iC₃H₇ H H CF₃ OCH₃ CH 52 NO₂ H H CF₃ OCH₃ CH 53 SO₂CH₃ H H CF₃ OCH₃ CH 54 SO₂N(CH₃)₂ H H CF₃ OCH₃ CH 55 Cl H H CF₃ OCH₃ CH 56 N(CH₃)SO₂CH₃ H H CF₃ OCH₃ CH 57 OSO₂CH₃ H H CF₃ OCH₃ CH 58 OSO₂N(CH₃)₂ H H CF₃ OCH₃ CH 59 CF₃ H H CF₃ OCH₃ CH 60 CF₂H H H CF₃ OCH₃ CH 61 CO₂CH₃ H H CF₂H OCH₃ N 62 CO₂C₂H₅ H H CF₂H CCH₃ N 63 CO₂iC₃H₇ H H CF₂H OCH₃ N 64 NO₂ H H CF₂H OCH₃ N 65 SO₂CH₃ H H CF₂H OCH₃ N 66 SO₂N(CH₃)₂ H H CF₂H OCH₃ N 67 Cl H H CF₂H OCH₃ N 68 N(CH₃)SO₂CH₃ H H CF₂H OCH₃ N 69 OSO₂CH₃ H H CF₂H OCH₃ N 70 OSO₂N(CH₃)₂ H H CF₂H OCH₃ N 71 CF₃ H H CF₂H OCH₃ N 72 CF₂H H H CF₂H OCH₃ N 73 CO₂CH₃ H H CF₂H OCH₃ CH 74 CO₂C₂H₅ H H CF₂H OCH₃ CH 75 CO₂iC₃H₇ H H CF₂H OCH₃ CH 76 NO₂ H H CF₂H OCH₃ CH 77 SO₂CH₃ H H CF₂H OCH₃ CH 78 SO₂N(CH₃)₂ H H CF₂H OCH₃ CH 79 Cl H H CF₂H OCH₃ CH 80 N(CH₃)SO₂CH₃ H H CF₂H OCH₃ CH 81 OSO₂CH₃ H H CF₂H OCH₃ CH 82 OSO₂N(CH₃)₂ H H CF₂H OCH₃ CH 83 CF₃ H H CF₂H OCH₃ CH 84 CF₂H H H CF₂H OCH₃ CH 85 CO₂CH₃ H H CF₂Cl OCH₃ N 86 CO₂C₂H₅ H H CF₂Cl OCH₃ N 87 CO₂iC₃H₇ H H CF₂Cl OCH₃ N 88 NO₂ H H CF₂Cl OCH₃ N 89 SO₂CH₃ H H CF₂Cl OCH₃ N 90 SO₂N(CH₃)₂ H H CF₂Cl OCH₃ N 91 Cl H H CF₂Cl OCH₃ N 92 N(CH₃)SO₂CH₃ H H CF₂Cl OCH₃ N 93 OSO₂CH₃ H H CF₂Cl OCH₃ N 94 OSO₂N(CH₃)₂ H H CF₂Cl OCH₃ N 95 CF₃ H H CF₂Cl OCH₃ N 96 CF₂H H H CF₂Cl OCH₃ N 97 CO₂CH₃ 3-F H Cl OCH₃ CH 98 CF₂CF₃ H H CH₃ OCH₃ N 99 CF₂CF₃ H H CH₃ OCH₃ N 100  SO₂C₂H₅ H H F OCH₃ CH

Examples of preferred compounds (b) are:

bromobutide

dimethenamid

isoxaben

propanil

glufosinate-ammonium

glyphosate

sulfosate

mefenacet

2,4-D

2,4-DB

2,4-DBEE

dichlorprop

dichlorprop-P

dichlorprop-P (2,4-DP-P)

fluroxypyr

MCPA

mecoprop

mecoprop-P

dicama

bentazone

clomazone

diflufenican

sulcotrione

phenmedipham

thiobencarb

quinclorac

quinmerac

acetochlor

alachlor

butachlor

metazachlor

metolachlor

pretilachlor

butroxydim

caloxydim

clethodim

cycloxydim

sethoxydim

tralkoxydim

2-{1[-2-(4-chlorophenoxy)propyloxyimino]butyl}-3-hydroxy-5-(2H-tetrahydrothiopyran-3-yl)-2-cyclohexen-1-one

pendimethalin

acifluorfen-sodium

bifenox

fluoroglycofen-ethyl

fomesafen

lactofen

chlortoluron

cycluron

dymrone

isoproturon

methabenzthiazuron

imazaquin

imazethabenz-methyl

imazethapyr

bromoxynil

ioxynil

clodinafop

cyhalofop-butyl

fenoxyprop-ethyl

fenoxaprop-P-ethyl

haloxyfop-P-methyl

cinidon-ethyl

flumiclorac-pentyl

flumipropyn

fluthiacet-methyl

pyridate

clopyralid

bispyribac-sodium

KIH-8555

KUH-920

flumetsulam

metosulam

amidosulfuron

azimsulfuron

bensulfuron-methyl

chlorimuron-ethyl

chlorsulfuron

cinosulfuron

cyclosulfamuron

ethoxysulfuron

flazasulfuron

halosulfuron-methyl

HOE-107925

imazosulfuron

metsulfuron-methyl

nicosulfuron

primisulfuron

prosulfuron

pyrazosulfuron-ethyl

rimsulfuron

thifensulfuron-methyl

triasulfuron

tribenuron-methyl

atrazine

cyanazine

terbuthylazine

benazolin

benfuresate

cafenstrole

cinemthylin

ammonium-bentazone

cloquintocet

ET-751

F-8426

KPP-314

The following compounds are particularly preferred:

2,4-D

dichlorprop-P

MCPA

mecoprop-P

dicamba

bentazone

diflufenican

sulcotrione

quinclorac

caloxydim

cycloxydim

sethoxydim

2-{1-[2-(4-chlorophenoxy)propyloxyimino]butyl}-3-hydroxy-5-(2H-tetrahydrothiopyran-3-yl)-2-cyclohexen-1-one

acifluorfen-sodium

fluoroglycofen-ethyl

bromoxynil

fenoxyprop-ethyl

cinidon-ethyl

amidosulfuron

bensulfuron-methyl

metsulfuron-methyl

nicosulfuron

pyrazosulfuron-ethyl

rimsulfuron

triasulfuron

tribenuron-methyl

atrazine

terbuthylazine

ammonium-bentazone

cloquintocet

The following compounds are very especially preferred:

dichlorprop-P

mecoprop-P

ammonium-bentazone

bentazone

diflufenican

quinclorac

2-(1-[2-(4-chlorophenoxy)propyloxyimino]butyl)-3-hydroxy-5-(2H-tetrahydrothiopyran-3-yl)-2-cyclohexen-1-one

caloxydim

cycloxydim

sethoxydim

fluoroglycofen-ethyl

cinidon-ethyl

nicosulfuron

pyrazosulfuron-ethyl

rimsulfuron

atrazine

terbuthylazine.

The present invention also relates to herbicidal compositions which comprise at least one herbicidally active amount of a sulfonylurea (a) of the above-described formula I or their environmentally compatible salts, a synergistically active amount of at least one above-described herbicidal compound (b) or its environmentally compatible salts, at least one liquid and/or solid carrier and, if desired, at least one adjuvant.

In the herbicidal mixtures and herbicidal compositions according to the invention, the sulfonylureas of the formula I or their environmentally compatible salts and the herbicidal compounds (b) or their environmentally compatible salts are used in such weight ratios that the desired synergistic effect is observed. The mixing ratios of sulfonylurea of the formula I and a herbicidal compound (b) are preferably 1: to 1:0.1 to 1:40, in particular 1:0.2 to 1:20, especially preferably 1:0.5 to 1:15.

The herbicidal mixtures and herbicidal compositions according to the invention which comprise the sulfonylureas of the formula I or their environmentally compatible salts of, for example, alkali metals, alkaline earth metals or ammonia and amines and the herbicidal compounds (b) or their environmentally compatible salts of, for example, alkali metals, alkaline earth metals or ammonia and amines are capable of effecting very good control of broad-leaved weeds and grass weeds in the crop rice without damaging the crop plants, an effect which is observed even when low rates of application are used.

Taking into consideration the versatility of the application methods, the herbicidal mixtures and herbicidal compositions according to the invention can also be employed in a further number of crop plants for eliminating undesirable plants. Suitable crops are, for example, the following:

Allium cepa, Ananas comosus, Arachis hypogaea, Asparagus officinalis, Beta vulgaris ssp. altissima, Beta vulgaris ssp. rapa, Brassica napus var. napus, Brassica napus var. napobrassica, Brassica rapa var. silvestris, Camellia sinensis, Carthamus tinctorius, Carya illinoinensis, Citrus limon, Citrus sinensis, Coffea arabica (Coffea canephora, Coffea liberica), Cucumis sativus, Cynodon dactylon, Daucus carota, Elaeis guineensis, Fragaria vesca, Glycine max, Gossypium hirsutum, (Gossypium arboreum, Gossypium herbaceum, Gossypium vitifolium), Helianthus annuus, Hevea brasiliensis, Hordeum vulgare, Humulus lupulus, Ipomoea batatas, Juglans regia, Lens culinaris, Linum usitatissimum, Lycopersicon lycopersicum, Malus spp., Manihot esculenta, Medicago sativa, Musa spp., Nicotiana tabacum (N.rustica), Olea europaea, Oryza sativa, Phaseolus lunatus, Phaseolus vulgaris, Picea abies, Pinus spp., Pisum sativum, Prunus avium, Prunus persica, Pyrus communis, Ribes sylvestre, Ricinus communis, Saccharum officinarum, Secale cereale, Solanum tuberosum, Sorghum bicolor (s. vulgare), Theobroma cacao, Trifolium pratense, Triticum aestivum, Triticum durum, Vicia faba, Vitis vinifera, Zea mays,

In addition, the herbicidal mixtures and herbicidal compositions according to the invention can also be used in crops which tolerate the action of herbicides due to breeding, including genetic engineering methods.

The herbicidal mixtures and herbicidal compositions according to the invention may be applied pre- or post-emergence. If the active ingredients are less well tolerated by certain crop plants, application techniques may be used in which the herbicidal compositions are sprayed, with the aid of the spraying equipment, in such a way that the active ingredients reach the leaves of the sensitive crop plants as little as possible while reaching the leaves of undesirable plants which grow underneath, or the bare soil surface (post-directed, lay-by).

The compositions according to the invention can be applied, for example in the form of ready-to-spray aqueous solutions, powders, suspensions, also highly-concentrated aqueous, oily or other suspensions or dispersions, emulsions, oil dispersions, pastes, dusts, materials for spreading or granules, by means of spraying, atomizing, dusting, spreading or pouring. The use forms depend on the intended purposes; in any case, they should guarantee the finest possible distribution of the active ingredients according to the invention.

Suitable inert additives are mineral oil fractions of medium to high boiling point, such as kerosene or diesel oil, furthermore coal tar oils and oils of vegetable or animal origin, aliphatic, cyclic and aromatic hydrocarbons, eg. paraffin, tetrahydronaphthalene, alkylated naphthalenes or their derivatives, alkylated benzenes or their derivatives, methanol, ethanol, propanol, butanol, cyclohexanol, cyclohexanone or strongly polar solvents such as N-methylpyrrolidone or water.

Aqueous use forms can be prepared from emulsion concentrates, suspensions, pastes, wettable powders or water-dispersible granules by adding water. To prepare emulsions, pastes or oil dispersions, the substances, as such or dissolved in an oil or solvent, can be homogenized in water by means of wetting agent, adhesive, dispersant or emulsifier. Alternatively, it is possible to prepare concentrates composed of active ingredient, wetting agent, adhesive, dispersant or emulsifier and, if desired, solvent or oil, which are suitable for dilution with water.

Suitable surfactants are the alkali, alkaline earth and ammonium salts of aromatic sulfonic acids, eg. ligno-, phenol-, naphthalene- and dibutylnaphthalenesulfonic acid, and of fatty acids, alkyl- and alkylarylsulfonates, alkyl, lauryl ether and fatty alcohol sulfates, and salts of sulfated hexa-, hepta- and octadecanols, and of fatty alcohol glycol ethers, condensates of sulfonated naphthalene and its derivatives with formaldehyde, condensates of naphthalene or of the naphthalenesulfonic acids with phenol and formaldehyde, polyoxyethylene octylphenol ether, ethoxylated isooctylphenol, octylphenol or nonylphenol, alkylphenyl polyglycol ethers, tributylphenyl polyglycol ether, alkylaryl polyether alcohols, isotridecyl alcohol, fatty alcohol/ethylene oxide condensates, ethoxylated castor oil, polyoxyethylene alkyl ethers or polyoxypropylene alkyl ethers, lauryl alcohol polyglycol ether acetate, sorbitol esters, lignosulfite waste liquors or methylcellulose.

Powders, materials for spreading, and dusts, can be prepared by mixing or concomitantly grinding the herbicidal mixture with a solid carrier.

Granules, eg. coated granules, impregnated granules and homogeneous granules, can be prepared by binding the active ingredient onto solid carriers. Solid carriers are mineral earths such as silicas, silica gels, silicates, talc, kaolin, limestone, lime, chalk, bole, loess, clay, dolomite, diatomaceous earth, calcium sulfate, magnesium sulfate, magnesium oxide, ground synthetic materials, fertilizers such as ammonium sulfate, ammonium phosphate, ammonium nitrate, ureas, and products of vegetable origin such as cereal meal, tree bark meal, wood meal and nutshell meal, cellulose powders, or other solid carriers.

In general, the formulations comprise 0.01 to 95% by weight, preferably 0.5 to 90% by weight, of the herbicidal mixture.

It may furthermore be advantageous to apply the herbicidal mixtures and herbicidal compositions according to the invention together in the form of a mixture with other crop protection agents, for example with agents for controlling pests or phytopathogenic fungi or bacteria. Also of interest is the miscibility with mineral salt solutions, which are employed for treating nutritional and trace element deficiencies. Non-phytotoxic oils and oil concentrates may also be added.

The rates of application of pure herbicidal mixture, ie. without formulation auxiliaries, are from 0.01 to 5 kg/ha, preferably 0.03 to 4 kg/ha, especially preferably 0.1 to 3.0 kg/ha, of active ingredient (a.i.), depending on the intended purpose, the season, the target plants and the growth stage.

The herbicidal compositions according to the invention are applied to the plants mainly by means of foliar sprays. They may be applied by customary spraying techniques using amounts of approximately 100 to 1000 1 of spray mixture per ha, for example using water as the carrier. An application of the compositions in the so-called “low-volume” and “ultra-low-volume” method is also possible, as is their application in the form of so-called granules.

USE EXAMPLE

The herbicide mixtures were applied post-emergence (foliar treatment), the sulfonylurea derivatives being applied in the form of 10 to 75 percent granules and the herbicidal compounds (b) in the formulation in which they exist as the commercial product.

The tests involved field trials with small plots at a sandy loam site (pH 6.2 to 7.0) or sandy clay (pH 5.0 to 6.7) site.

The weeds were present in different sizes and development stages, their height being, on average, 5 to 20 cm, depending on the plant habit.

The herbicidal compositions were applied alone and also jointly, in the latter case sometimes as a tank mix, sometimes as a ready-mix. This was done using water (350 1/ha) as the distribution vehicle, depending on the formulation of the active ingredients in the form of emulsions, aqueous solutions or suspensions. Application was effected with the aid of a mobile plot sprayer.

The test period extended over 3 to 8 weeks, and the stands were also observed at later dates.

The damage caused by the herbicidal compositions was assessed using a scale from 0% to 100% in comparison with untreated control plots. Thus, 0 means no damage, and 100 means complete destruction of the plants.

The examples which follow show the activity of the herbicidal compositions which can be used according to the invention without excluding the possibility of other uses.

In these examples, the method of S. R. Colby (1967): Calculating synergistic and antagonistic responses of herbicide combinations, Weeds 15, 20 et seq. was used to determine the value E which can be expected when an action of the individual active ingredients is merely additive.

The calculation was carried out using the formula: $E = {X + Y - \frac{XY}{100}}$

where

X=percentage activity using preparation A at a rate of application a

Y=percentage activity using preparation B at a rate of application b

E=expected activity (in %) caused by A+B at rate of application of a+b.

If the observed value exceeds the value E calculated using Colby's formula, a synergistic effect is present.

The herbicidal compositions according to the invention have a herbicidal activity which is higher than what can be expected when applying Colby's formula compared with the observed activities of the individual components . . . used alone. 

We claim:
 1. A herbicidal composition comprising: a) at least one sulfonylurea of the formula I:

 wherein: R¹ is C₁-C₆-alkyl which carries one to five of the following groups: methoxy, ethoxy, SO₂CH₃, cyano, chlorine, fluorine SCH₃, S(O)CH₃; halogen; a group ER⁶ where E is O, S or NR⁷; COOR⁸; N₂; S(O)_(o)R⁹; SO₂NR¹⁰R¹¹; CONR¹⁰R¹¹; R² is hydrogen, C₁-C₄-alkyl, C₂-C₄-alkenyl, C₂-C₄-alkynyl, halogen, C₁-C₄-alkoxy, C₁-C₄-haloalkoxy, C₁-C₄-haloalkyl, C₁-C₂-alkylsulfonyl, nitro, cyano or C₁-C₄-alkylthio; R³ is F, CF₃, CF₂Cl, CF₂H, OCF₃, OCF₂Cl or, if R¹ is CO₂CH₃ and R² is simultaneously fluorine, R³ is Cl, or, if R¹ is CH₂CF₃ or CF₂CF₃, R³ is methyl, or, if R⁴ is OCF₃ or OCF₂Cl, R³ is OCF₂H or OCF₂Br; R⁴ is C₁-C₂-alkoxy, C₁-C₂-alkyl, C₁-C₂-alkylthio, C₁-C₂-alkylamino, di-C₁-C₂-alkylamino, halogen, C₁-C₂-haloalkyl, C₁-C₂-haloalkoxy; R⁵ is hydrogen, C₁-C₂-alkoxy, C₁-C₄-alkyl; R⁶ is C₁-C₄-alkyl, C₂-C₄-alkenyl, C₂-C₄-alkynyl or C₃-C₆-cycloalkyl, where these groups may carry 1 to 5 halogen atoms, with the exception of allyl, difluoromethoxy, chlorodifluoromethoxy and 2-cloroethoxy when E is O or S; or in the event that E is O or NR⁷, R⁶ is furthermore methylsulfonyl, ethylsulfonyl, trifluoromethylsulfonyl, allylsulfonyl, propargylsulfonyl or dimethylsulfamoyl; R⁷ is hydrogen, methyl or ethyl; R⁸ is C₁-C₆-alkyl, which may carry up to three of the following radicals: halogen, C₁-C₄-alkoxy, C₁-C₄-alkylthio, C₁-C₄-haloalkoxy, C₁-C₄-alkoxy-C₁-C₄-alkoxy, C₃-C₇-cycloalkyl and/or phenyl; C₅-C₇-cycloalkyl which may carry up to three C₁-C₄-alkyl groups; C₃-C₆-alkenyl or C₃-C₆-alkynyl; R⁹is C₁-C₆-alkyl, which may carry up to three of the following radicals: halogen, C₁-C₄-alkoxy, C₁-C₄-alkylthio, C₁-C₄-haloalkoxy, C₁-C₄-alkoxy-C₁-C₄-alkoxy, C₃C₇-cycloalkyl and/or phenyl C₅-C₇-cycloalkyl which may carry up to three C₁-C₄-alkyl groups; C₃-C₆-alkenyl or C₃-C₆-alkynyl; R¹⁰ is hydrogen, C₁-C₂-alkoxy, C₁-C₆-alkyl, or together with R¹¹ is a C₄-C₆-alkylene, chain in which one methylene group may be replaced by an oxygen atom or a C₁-C₄-alkylimino group; R¹¹ is C₁-C₄-alkyl which may carry one to four halogen or C₁-C₄-alkoxy radicals; C₃-C₆-cycloalkyl; n 0-3; o is 1 or 2; Z is N or CH, or an enviromentally compatible salt of I, and b) at least one herbicidal compound selected from groups b₂, b₇ to b₉, b₂₁, b₂₆, b₂₇, b₃₀, b₃₆ and b₃₇: b₂) amides: allidochlor (CDAA), benzoylprop-ethyl, bromobutide, clorthiamid, dimepiperate, dimethenamid, diphenamid, etobenzanid (benzchlomet), flamprop-methyl, fosamin, isoxaben, monalide, naptalame, propamid (propyzamid and propanil; b₇) benozoic acids: cloramben and dicamba; b₈) benzothiadiazinones: bentazone; b₉) bleachers: clomazone (dimethazone), diflufenican, flurocloridone, flupoxam, fluridone, pyrazolate and sulcotrione (clormesulone); b₂₁) ureas: benzthiazuron, buturon, chlorbromuron, chloroxuron, chlortoluron, cumyluron, bibenzyluron, cycluron, dimefuron, diuron, dymrone, ethidimuron, fenuron, fluormeturon, isoproturon, isouron, karbutilate, linuron, methabenzthiazuron, metobenzuron, metoxuron, monolinuron, monuron, siduron, tebuthiuron and trimeturon; b₂₆) phenols: bromoxynil and ioxynil; b₂₇) phenoxyphenoxypropionic esters: clodinafop, cyhalofop-butyl, diclofop-methyl, fenoxaprop-ethyl, fenoxapro-P-ethyl, fenthiaprop-ethyl, fluazifop-butyl, fluazifop-P-butuyl, haloxyfop-ethoxyethyl, haloxyfop-methyl, haloxyfop-P-methyl, isoxapyrifop, propaquizafop, quizalofop-ethyl, quizalofop-P-ethyl and quizalofop-tefuryl; b₃₀) protoporphyrinogen IX oxidase inhibitors: benzofenap, cirnidon-ethyl, flumiclorac-pentyl, flumioxazin, flumipropyn, flupropacil, fluthiacet-methyl, pyrazoxyfen, sulfentrazone and tridiazimin; b₃₆) sulfonylureas: amidosulfuron, azimsulfuron, bensulfuron-methyl, clorimuron-ethyl, clorsulfuron, cinosulfuron, cyclosulfuron, ethametsulfuron-methyl, ethoxysulfuron, flazasulfuron, halosulfuron-methyl, imazosulfuron, metsulfuron-methyl, nicosulfuron, primisulfuron, prosulfuron, pyrazosulfuron-ethyl, rimsulfuron, sulfometuron-methyl thifensulfuron-methyl, triasulfuron, tribenuron-methyl and trifusulfuron-methyl; b₃₇) triazines: ametryn, atrazine, aziprotryn, cyanazine cyprazine, desmetryn, dimethamethryn, dipropetryn, eglinazine-ethyl, hexazinon, procyazine, prometon, prometryn, propazine, secbumeton, simazine, simetryn, terbumeton, terbutryn, terbuthylazine and trietazine; or an enviromentally compatible salt of the herbicidal compound, in a synergistically active amount.
 2. The herbicidal composition defined in claim 1, comprising a sulfonylurea of the formula I wherein: R¹ is CO₂CH₃, CO₂C₂H₅, CO₂iC₃H₇, CF₃, CF₂H, CH₂CF₃, CF₂CF₃, OSO₂CH₃, OSO₂N(CH₃)₂, Cl, NO₂, SO₂N(CH₃)₂, SO₂CH₃, SO₂C₂H₅ and N(CH₃)SO₂CH₃, R² is hydrogen, halogen or methyl, R³ is CF₂H, OCF₃, OCF₂Cl, CF₃, or, if R¹ is CO₂CH₃ and R² is simultaneously fluorine, R³ is Cl, or, if R¹ is CH₂CF₃ or CF₂CF₃, R³ is methyl, R⁴ is OCH₃, and R⁵ is hydrogen.
 3. The herbicidal composition defined in claim 1, comprising a sulfonylurea of the formula I wherein: R¹ is halogen, a group ER⁶, CO₂R⁸, SO₂CH₃ or SO₂C₂H₅, R² is hydrogen, R³ is F, R⁴ is OCF₃, OCF₂Cl or OCH₃, and R⁵ is hydrogen.
 4. The herbicidal composition defined in claim 1, comprising a sulfonylurea of the formula I wherein: R¹ is CF₃, R² is hydrogen, R³ is CF₃, R⁴ is OCH₃, R⁵ is hydrogen, and Z is N.
 5. The herbicidal composition defined in claim 1, wherein the herbicidal compound (b) is selected from the group consisting of: bromobutide, dimethenamid, isoxaben, propanil, dicamba, bentazone, clomazone, diflufenican, flurochloridone, sulcotrione, chlortoluron, cycluron, dymrone, isoproturon, methabenzthiazuron, bromoxynil, ioxynil, clodinafop, cyhalofop-butyl, fenoxaprop-ethyl, fenoxaprop-p-ethyl, haloxyfop-p-methyl, cinidon-ethyl, flumiclorac-pentyl, flumipropyn, fluthiacet-methyl, amidosulfuron, azimsulfuron, bensulfuron-methyl, chlorimuron-ethyl, chlorsulfuron, cinosulfuron, cyclosulfuron, ethoxysulfuron, flazasulfuron, halosulfuron-methyl, imazosulfuron, metsulfuron-methyl, nicosulfuron, primisulfuron, prosulfuron, pyrazosulfuron-ethyl, rimsulfuron, thifensulfuron-methyl, triasulfuron, tribenuron-methyl, atrazine, cyanazine, terbutylazine, ammonium-bentazone, cloquintocet, ET-751, F-8426 and KPP-314.
 6. The herbicidal composition defined in claim 1, wherein the herbicidal compound (b) is selected from the group consisting of: dicamba, bentazone, diflufenican, sulcotrione, bromoxynil, fenoxaprop-ethyl, cinidon-ethyl, amidosulfuron, bensulfuron-methyl, metsulfuron-methyl, nicosulfuron, pyrazosulfuron-ethyl, rimsulfuron, triasulfuron, tribenuron-methyl, atrazine, ammonium-bentazone and cloquintocet.
 7. The herbicidal composition defined in claim 1, comprising the sulfonylurea (a) and the one or more herbicidal compounds (b) in a weight ratio of 1:0.1 to 1:40.
 8. The herbicidal composition defined in claim 1, comprising the sulfonylurea (a) and the one or more herbicidal compounds (b) in a weight ratio of 1:0.1 to 1:20.
 9. A herbicidal composition comprising a) a herbicidally active amount on a sulfonylurea of the formula I as defined in claim 1, b) a synergistically active amount of at least one of the herbicidal compounds (b) defined in claim 1, at least one liquid or solid carrier and optionally at least one adjuvant.
 10. The herbicidal composition defined in claim 9, wherein the sulfonylurea (a) and one or more of the herbicidal compounds (b) are present in a weight ratio of 1:0.1 to 1:40.
 11. The herbicidal composition defined in claim 9, wherein the sulfonylurea (a) and one or more of the herbicidal compounds (b) are present in a weight ratio of 1:0.1 to 1:40.
 12. The herbicidal composition defined in claim 1, wherein at least one of the herbicidal compounds (b) is a benzoic acid selected from the group consisting of cloramben and dicamba.
 13. The herbicidal composition defined in claim 12, wherein the weight ratio of the sulfonylurea to the benzoic acid is from 1:0.1 to 1:40.
 14. The herbicidal composition defined in claim 12, wherein the weight ratio of the sulfonylurea to benzoic acid is from 1:0.2 to 1:20.
 15. The herbicidal composition defined in claim 1, wherein component b) is at least one compound selected from the groups: b₂) amides: dimethenamid; b₇) benzoic acids: cloramben and dicamba; b₈) benzothiadiazinones: bentazone; b₉) bleachers: clomazone (dimethazone), diflufenican and sulcotrione (chlormesulone); b₂₁) ureas: benzthiazuron, buturon, chlorbromuron, chloroxuron, chlortoluron, cumyluron, bibenzyluron, cycluron, dimefuron, diuron, dymrone, ethidimuron, fenuron, fluormeturon, isoproturon, isouron, linuron, methabenzthiazuron, metobenzuron, metoxuron, monolinuron, monuron, siduron, tebuthiuron and trimeturon; b₂₆) phenols: bromoxynil and ioxynil; b₂₇) phenoxyphenoxypropionic esters: clodinafop, cyhalofop-butyl, diclofop-methyl, fenoxaprop-ethyl, fenoxaprop-P-ethyl, fenthiaprop-ethyl, fluazifop-butyl, fluazifop-P-butyl, haloxyfop-ethoxyethyl, haloxyfop-methyl, haloxyfop-P-methyl, isoxapyrifop, propaquizafop, quizalofop-ethyl, quizalofop-P-ethyl and quizalofop-tefuryl; b₃₀) protoporphyrinogen IX oxidase inhibitors: cinidon-ethyl, flumiclorac-pentyl, flumioxazin, flumipropyn, fluthiacet-methyl, sulfentrazone and thidiazimin; b₃₆) sulfonylureas: amidosulfuron, azimsulfuron, bensulfuron-methyl, chlorimuron-ethyl, chlorsulfuron, cinosulfuron, cyclosulfuron, ethametsulfuron-methyl, ethoxysulfuron, flazasulfuron, halosulfuron-methyl, imazosulfuron, metsulfuron-methyl, nicosulfuron, primisulfuron, prosulfuron, pyrazosulfuron-ethyl, rimsulfuron, sulfometuron-methyl, thifensulfuron-methyl, triasulfuron, tribenuron-methyl and triflusulfuron-methyl; b₃₇) triazines: atrazine, aziprotryn, cyanazine, cyprazine, desmetryn, dimethamethryn, dipropetryn, eglinazine-ethyl, procyazine, prometon, prometryn, propazine, secbumeton, simazine, simetryn, terbumeton, terbutryn, terbuthylazine and trietazine.
 16. The herbicidal composition defined in claim 1, wherein component b) is at least one compound selected from the groups: b₂) amides: dimethenamid; b₇) benzoic acids: dicamba; b₈) benzothiadiazinones: bentazone; b₉) bleachers: clomazone (dimethazone), diflufenican and sulcotrione (chlormesulone); b₂₁) ureas: diuron, dymrone, isoproturon, methabenzthiazuron and metoxuron; b₂₆) phenols: bromoxynil and ioxynil; b₂₇) phenoxyphenoxypropionic esters: clodinafop, diclofop-methyl, fenoxaprop-ethyl, fenoxaprop-P-ethyl, fluazifop-butyl, fluazifop-P-butyl, haloxyfop-methyl and haloxyfop-P-methyl; b₃₀) protoporphyrinogen IX oxidase inhibitors: cinidon-ethyl, flumioxazin, fluthiacet-methyl and sulfentrazone; b₃₆) sulfonylureas: amidosulfuron, chlorsulfuron, flazasulfuron, halosulfuron-methyl, metsulfuron-methyl, nicosulfuron, primisulfuron, prosulfuron, rimsulfuron, sulfometuron-methyl, thifensulfuron-methyl, triasulfuron and tribenuron-methyl; b₃₇) triazines: atrazine, cyanazine, simazine and terbuthylazine.
 17. The herbicidal composition defined in claim 1, wherein component b) is at least one compound selected from the group of: dicamba, bentazone, sulcotrione (chlormesulone), dimethenamid, isoproturon, bromoxynil, fenoxaprop-P-ethyl, clodinafop, cinidon-ethyl, halosulfuron-methyl and atrazine.
 18. The herbicidal composition defined in claim 1, comprising a) a sulfonylurea of formula (I) wherein R¹ is trifluoromethyl, R² is hydrogen, R³ is trifluoromethyl, R⁴ is methoxy, R⁵ is hydrogen and Z is nitrogen, and b) at least one compound selected from the group of: dicamba, bentazone, sulcotrione (chlormesulone), dimethenamid, isoproturon, bromoxynil, fenoxaprop-P-ethyl, clodinafop, cinidon-ethyl, halosulfuron-methyl and atrazine.
 19. A method of controlling undesirable vegetation, which comprises applying the sulfonylurea (a) defined in claim 1 and one or more of the herbicidal compounds (b) defined in claim 1 before, during or after the emergence of undesirable plants, either simultaneously or in succession.
 20. A method of controlling undesirable vegetation, which comprises treating the leaves of crop plants and of undesired plants with the sulfonylurea (a) defined in claim 1 and one or more of the herbicidal compounds (b) defined in claim 1, either simultaneously or in succession. 